In U.S. Pat. No. 3,638,221, which is assigned to the assignee of the present invention, a magnetic key switch is disclosed in which a saturable magnetic core is permanently mounted in the housing of a switch. A pair of permanent magnets are attached to the depressible key stem of the switch so that when the key stem is not depressed the saturable core is saturated, and, thus, an output signal will not be produced on a sense line which is coupled to the core adjacent to a drive line which is also coupled to the core and to a source of electrical pulses. When the key stem is depressed the core is unsaturated, since the magnets are then displaced from it, and an output signal is produced on the sense lines due to inductive coupling between the sense line and the drive line. While the switch of the above-noted patent has proved to be highly advantageous from a functional standpoint it is been found to be desirable in certain applications to be able to separate the despressible key stem section from the magnetic core, sense and drive line section of the key switch so that replacement of a mechanical component of the switch, such as the plunger return spring, can be made, when necessary, without complete disassembly of the switch and without unsoldering the drive and sense wires from a printed circuit board or other type of connector. In U.S. Pat. application Ser. No. 259,209, which is also assigned to the assignee of the present invention, several versions of a support assembly suitable for supporting the magnetic core and the associated sense and drive windings of a magnetic key switch are disclosed. However, the support assemblies of the above-noted patent application were not constructed so as to be selectively retainable and selectively removable from the housing of the key switch.
In order to facilitate repair and reduce repair cost the drive and sense lines and the magnetic core of the switch of the present invention are supported by a support assembly which may be selectively retained in the housing of the switch during handling and storage, and which may be easily removed from the housing if repair or connection to a printed circuit board is desired. In the highly competitive switch business the desirable feature of a selectively removable unitary support assembly for the magnetic core and the associated sense and drive line wires of a magnetic key switch must be provided at a relatively low cost, and this is also achieved by the present invention.